[Relation of bacterial flora between upper and lower respiratory tracts in patients with long-term tracheostomy]

Throat secretions (TS) and bronchial secretions aspirated from tracheostomy (TSTA) were cultured at the same time in 9 subjects with long term tracheostomy every two weeks from January, 1990 to December, 1990. Total number of each examination in TS and TSTA were 200 times. Mean number of bacteria isolated by single culture were 2.9 strains in TS and 1.8 strains in TSTA. Isolated bacteria were mainly alpha-Streptococcus (84.8%) and Neisseria (69%) in TS, and Pseudomonas aeruginosa (53.5%) and Serratia marcescens (30%) in TSTA. Only 20% of P. aeruginosa or S. marcescens in TSTA were isolated from TS. In 8 cases of 9, P. aeruginosa in TSTA were isolated with every time or long term. There were 14 episodes of respiratory infections in 6 cases. P. aeruginosa were causative organisms in 7 episodes. It suggests that P. aeruginosa tended to colonize in lower respiratory tracts of the patients with long term tracheostomy and to become causative organisms in respiratory infections.